1. Field of the Invention
The present invention relates to a drive axle and in particular to a relatively simple single speed single reduction drive axle which may be quickly converted into a shiftable two speed drive axle or a planetary double reduction drive axle.
2. Description of the Prior Art
Single reduction drive axles for both relatively light duty vehicles such as passenger cars and for heavy duty vehicles such as trucks are well known in the prior art as may be seen by reference to U.S. Pat. No. 3,838,751 assigned to the assignee of this invention and hereby incorporated by reference.
Shiftable two speed drive axles of the planetary double reduction type and drive axles of the planetary double reduction type, usually utilized in heavy duty vehicles such as trucks, are also well known in the prior art. Examples of such drive axles may be seen by reference to U.S. Pat. Nos. 2,754,692; 3,195,371 and 3,265,173, all assigned to the assignee of this invention and all hereby incorporated by reference.
Single speed single reduction axles are highly advantageous in situations not requiring additional drive train ratios nor low, i.e. deep, reductions in view of their relative simplicity of construction, low cost and ease of operation.
Shiftable two speed axles of the planetary double reduction type and planetary double reduction axles are highly advantageous in situations requiring additional drive train ratios and/or relatively deep reductions. Such axles are widely commercially accepted, especially for vehicles utilizing simple rather than compound transmissions. Such axles, and the vehicles in which they are installed, in view of the great versitality of duty cycles for which they are suited, usually command a considerably higher resale value despite the higher cost, more complicated construction and requirement for greater operator skill and training relative to a single speed single reduction drive axle.
Accordingly, there has developed a demand for a single speed single reduction drive axle which can be quickly and easily converted into a shiftable two speed axle of the planetary double reduction type or into a single speed planetary double reduction type by that segment of the truck industry desiring the simplicity of operation and relative low cost of a single speed axle but preferring the increased resale value and/or the ability to change duty cycles of a two speed axle. The rental or lease truck fleet owners are an example of this segment of the truck market. The agricultural industry is an example of those purchasing used vehicles and requiring two speed axles.